Method for manufacturing a mascara brush

ABSTRACT

A method for manufacturing a brush for applying a product to the eyelashes and/or eyebrows. The brush includes a core having two branches which are twisted together and bristles clamped between the branches, and the method includes the steps of a) producing a brush blank, of which the envelope surface defines at least one first groove, and b) producing, in the blank obtained at a), at least one second groove intersecting the first one, at least one of the grooves being a helical groove.

The present invention relates to brushes for applying a cosmetic product to the eyelashes or eyebrows, in particular a makeup or care product, for example mascara, and to corresponding packaging and application devices.

A large number of applicators are known in which the brush comprises a core formed by two branches of a metal wire that are twisted together and grip bristles.

Since the bristles used are generally the same length, once the branches are twisted, the brush has an envelope surface in the form of a cylinder of revolution. Such a form has limited effectiveness in terms of loading the eyelashes and separation. Efforts have thus been made to give the envelope surface more complex shapes so as to form on the brush, after wiping, zones that are more heavily laden with product, making it possible to properly load the eyelashes, and zones that are less heavily laden, these being usable to separate the eyelashes. Finding the shape that results in the optimum makeup result requires numerous tests, since many factors come into play.

In addition, it is economically advantageous for the brush to be able to be manufactured quickly and easily.

Lastly, the brush must remain simple to use.

Numerous brushes have been proposed, with notches machined in the longitudinal direction of the core. The patent application FR 2 605 505 discloses a brush in which the envelope surface of the regions situated between two crests is a planar surface or a surface with a concave profile. An envelope surface is thus obtained which, in cross section, has various shapes such as a triangle, a square or a hexagon, with straight or concave sides.

It is known from U.S. Pat. No. 5,595,198 to produce a brush with helical grooves. The latter are produced by firstly machining a blank with two rectilinear and diametrically opposite longitudinal grooves. The core is then twisted about its axis, which transforms the rectilinear grooves into longitudinal grooves.

U.S. Pat. No. 6,279,583 provides a similar teaching. In an intermediate state of manufacture, helical grooves are cut in a blank. The core is then further twisted so as to intersperse the bristles so that the final brush exhibits a substantially uniform envelope surface

U.S. Pat. No. 5,551,456 discloses a brush obtained by twisting a blank that has a flattened cross section.

To date, there is still a need to improve brushes for applying a cosmetic product to the eyelashes and/or eyebrows, in particular to benefit from brushes that are capable of satisfactorily making up the eyelashes and eyebrows, by providing a sufficient load of product, and that are easy to use.

The invention aims to meet this need and, according to one of its aspects, relates to a method for manufacturing a brush for applying a product to the eyelashes and/or eyebrows, comprising a core having two branches which are twisted together and bristles clamped between the branches, this method comprising the steps of:

a) producing a brush blank, of which the envelope surface defines at least one first groove,

b) producing, in the blank obtained at a), at least one second groove intersecting the first one, at least one of said grooves being a helical groove, preferably the first one.

By virtue of the invention, a brush is obtained that comprises product storage zones in the grooves above, for providing a sufficient charge of product, and zones that are loaded with less product, in the area outside said grooves, and that can be used for separating the eyelashes and/or eyebrows.

The helical trajectory of the helical groove ensures gradual loading of the eyelashes.

The final brush, i.e. as manufactured and introduced in a container containing the product to be applied, comprises the at least one helical groove and the at least one second groove that intersects the first one.

A “groove” is to be understood as meaning a hollowed-out relief when the brush is observed in cross section.

The term “helical” is to be understood as meaning a groove which runs around the longitudinal axis of the core as it proceeds along the latter. It can be a helix with a fixed or variable pitch and/or with a constant or variable radius.

The pitch is preferably fixed if one considers the helix defined by the bottom of the groove. The radius of the helix is likewise preferably fixed if one considers the same helix. The bottom of the groove can thus be situated at a constant distance from the core, all the way along the groove.

The depth of the groove, with respect to the envelope surface outside the groove, can also be variable.

The helical groove can be obtained by machining the blank with a relative helical displacement between the tool and the brush. The groove formed at step a) can thus be helical or rectilinear, in which case the groove formed at step b) is helical.

Alternatively, the helical groove can also be obtained by machining a longitudinal groove, then twisting the blank about its longitudinal axis in order to give this groove a helical trajectory. In this case, the groove formed at step a) is helical.

The method according to the invention can comprise the production of several helical grooves, in particular an uneven number of said grooves, preferably between 2 and 10. Said helical grooves can be distributed at equal angles about the longitudinal axis of the core.

The or at least one of said first grooves can have, in cross section, a V-shaped profile open towards the outside, with flanks, for example convex flanks, arranged opposite each other.

The or each first groove, when helical, can extend at least 180° about the longitudinal axis of the core, in particular between a half turn and four turns about the longitudinal axis of the core, preferably by 360°.

The or each first groove can extend along at least half of the length of the part of the core carrying the bristles, preferably along 9/10 or more of this length.

The or each first groove can extend as far as the proximal end of the portion carrying the bristles but can remain set back from the distal end of said portion.

The method according to the invention comprises the production of one or more second grooves, in particular an even number of second grooves, preferably between 2 and 10. The second grooves can be distributed at equal angles about the longitudinal axis of the core.

The or at least one of the second grooves can have, in cross section, a V-shaped profile open towards the outside, in particular with flat opposite flanks.

The one or more second grooves can have rectilinear axes or, alternatively, non-rectilinear axes.

The one or more second grooves can thus be helical and in particular can intersect the one or more first grooves with an angle of between 60° and 120°, preferably close to or equal to 90°.

All of the second grooves can be identical, except for a rotation about the longitudinal axis of the core.

Alternatively, the brush comprises second grooves which differ from one another, for example with one being helical and the other rectilinear.

The number of second grooves is preferably less than or equal to the number of first grooves, preferably less than said number.

The second grooves, when helical, can have the same helix angle as the first grooves, apart from the sign. The pitch can be the same or different, likewise the radius.

The invention also relates to a brush for applying a product to the eyelashes and/or eyebrows, in particular obtained by the method according to the invention as defined above, comprising a core having two branches which are twisted together and bristles held by the core, defining an envelope surface having at least one first helical groove and a second groove, which is helical or non-helical, in particular rectilinear, intersecting the first one.

The brush can comprise several first grooves and at least one second groove or at least one first groove and several second grooves, preferably several first grooves and several second grooves, the grooves defining a grid pattern on the envelope surface on account of their intersections.

The brush can have any one of the features set forth above, irrespective of the way in which it is manufactured. Thus, for example, the grooves intersect substantially at 90°.

The invention likewise relates to a packaging and application device comprising:

-   -   a container containing a cosmetic product to be applied to the         eyelashes or eyebrows,     -   a brush according to the invention.

Such a brush comprises the at least one helical groove and the at least one second groove intersecting the first.

The container can be provided with a wiping member for removing the excess product present on the brush.

The invention will be better understood from reading the following detailed description of non-limiting illustrative embodiments thereof and from examining the appended drawing, in which:

FIG. 1 shows an example of a packaging and application device according to the invention, in schematic longitudinal section,

FIG. 2 is a side view of an example of a brush according to the invention,

FIGS. 3 and 4 show a brush blank used in the manufacture of the brush,

FIG. 5 is a perspective view of the blank, after a first treatment step,

FIG. 6 is a front view along VI in FIG. 5,

FIG. 7 shows a perspective view of the treated blank from FIGS. 5 and 6, after the core has been twisted,

FIG. 8 shows the blank from FIG. 7, after continuation of the treatment,

FIG. 9 is a front view along IX in FIG. 8,

FIGS. 10 and 11 are perspective views of other examples of brushes, and

FIG. 12 is a front view along XII in FIG. 11.

In the rest of the description, identical elements or elements having equivalent functions bear the same reference signs. Their description is not repeated for each of the figures, only the main differences between the embodiments being mentioned.

The packaging and application device 1 shown in FIG. 1 has a container 2 containing a product P to be applied to the eyelashes or eyebrows and an applicator 3 which, in the example in question, can be fixed removably to the container 2. The product P comprises for example one or more pigments, in particular an iron oxide. It is preferably a mascara.

The applicator 3 has a stem 5 of longitudinal axis Y, which is provided at a distal end 5 a with a brush 10 according to the invention, and is provided at the other end with a gripping member 11, which likewise forms a cap for closing the container 2 in a sealed manner. As can be seen in particular in FIG. 1, the latter has a body 13 which is provided at the top with a threaded neck 14 onto which the gripping member 11 can be screwed in order to close the container 2. In a variant, the applicator can be fixed to the container in some other way.

As is shown, the neck 14 is able to receive a wiping member 20 which, for example, is attached thereto. This wiping member 20 has a lip 26 defining a wiping orifice with a diameter adapted to that of the stem 5. The diameter of the stem 5 is, for example, between 3 and 8 mm.

The brush 10 can be fixed, in a conventional manner, in a seat provided at the distal end 5 a of the stem 5, which is advantageously made of a thermoplastic material.

The brush 10 has a twisted metal core 40 formed by two branches which are twisted together and which between them grip bristles 41. It can be a stainless steel wire.

The core 40 is fixed at one end in the corresponding seat of the stem 5 by a proximal portion 40 a that does not have bristles, it being possible for said portion to have a length of the order of 8 mm, for example.

As is illustrated in FIG. 2, the free ends of the bristles 41 define the envelope surface S of the brush 10.

The longitudinal axis X of the core 40 of the brush 10 is rectilinear in the example in question.

The envelope surface S defines at least one helical groove 50 which extends along almost the entire length of the portion 40 c of the core carrying the bristles and which makes at least a half turn about the longitudinal axis X of the core between the distal and proximal ends thereof, in this case a complete turn.

In the example in question, the brush 10 comprises five such helical grooves 50 distributed at equal angles about the axis X.

The brush 10 also has rectilinear grooves 80 distributed at equal angles and intersecting the grooves 50.

The brush 10 can be manufactured by proceeding as follows.

First of all, a first brush blank 10 ⁽¹⁾ as shown in FIG. 3 is formed by machining a brush with an envelope surface as a cylinder of revolution about the longitudinal axis X. This blank 10 ⁽¹⁾ shown in FIG. 3 has a conical distal portion 60 converging towards the distal end 40 b of the core.

The blank 10 ⁽¹⁾ has a proximal portion 62 with a likewise conical shape converging towards the proximal end of the brush.

The portions 60 and 62 are connected by an intermediate portion 61 which is longer than the portions 60 and 62 and which has a slightly conical shape converging towards the distal end of the brush.

The total length L of the portion 40 c of the core carrying the bristles 41 is for example between 25 and 30 mm, for example of the order of 27 mm.

The greatest diameter D of the blank 10 ⁽¹⁾ is, for example, between 8 and 10 mm, for example of the order of 9 mm.

The greatest diameter D is measured at a distance l from the proximal end of the portion 40 c of the core. The distance l is preferably between 2 and 6 mm, for example of the order of 4 mm in the example in question.

The diameter d_(d) of the distal end face of the blank 10 ⁽¹⁾ is, for example, between 8 and 10 mm, for example of the order of 9 mm.

The diameter d_(p) at the proximal end of the envelope surface is, for example, between 4 and 6 mm, for example of the order of 5 mm.

The diameter d_(d) at the distal end is for example between 4 and 5 mm, for example of the order of 4.5 mm, where preferably d_(p)>d_(d).

The distal portion 60 converges more than the intermediate portion 61.

The diameter d_(j) at the junction between the portions 61 and 60 is less than the diameter D and is for example between 7 and 9 mm, for example of the order of 8 mm.

The junction between the portions 60 and 61 is situated at a distance 1, from the distal end of the core preferably greater than the distance l. For example, l_(j) is between 5 and 8 mm, for example of the order of 6.5 mm.

The blank 10 ⁽¹⁾ can also be produced with another shape, in particular with several relative maxima for its cross section.

Once the blank 10 ⁽¹⁾ of FIGS. 3 and 4 has been produced, the grooves 50 are machined in it first of all in the rectilinear state, as illustrated in FIGS. 5 and 6, in order to obtain a blank 10 ⁽²⁾. In the example in question, these grooves 50 are five in number and are distributed at equal angles about the axis X of the blank.

The depth of each of the grooves 50 corresponds substantially to the difference D-d_(d), and it can be slightly greater than D-d_(d), as can be seen in FIG. 6.

Each groove 50 has, in cross section, a substantially V-shaped profile as illustrated in FIG. 6, with opposite flanks 51.

Each flank 51 is convex towards the opposite flank 51 and has a profile in the shape of an arc of a circle. The bottom of each groove 50 has a profile in the shape of an arc of a circle with the concavity facing outwards. Each groove 50 is symmetrical with respect to a median plane containing the axis X.

The distal end 50 a of the grooves 50 is situated at a non-zero distance t from the distal end of the portion 40 c, as can be seen in FIG. 5. The grooves 50 go as far as the proximal end of the portion 40 c.

Once the grooves 50 have been produced in order to obtain the blank 10 ⁽²⁾, the portion 40 c of the core is twisted about its axis X, which deforms the whole brush and in particular the grooves 50, which assume a helical configuration as shown in FIG. 7. This additional twisting is effected in the same direction as the twisting of the branches of the core 40.

In the example in question, this twisting entails a complete turn of the proximal end with respect to the distal end of the core portion 40 c. The blank 10 ⁽³⁾ is obtained.

Thereafter, according to the invention, and as illustrated in FIG. 8, at least one other groove 80 is machined in the blank 10 ⁽³⁾ in such a way as to intersect at least one of the helical grooves 50.

In the example in FIG. 8, four grooves 80 are machined which have axes parallel to the axis X and are distributed at equal angles about the axis X.

As illustrated, each groove 80 preferably has, in cross section, a V-shaped profile as illustrated in FIG. 9, with flat opposite flanks 81. The grooves 80 are rectilinear with a longitudinal axis parallel to the axis X, and the bottom of the grooves is situated at a distance from the axis X that is substantially the same as the distance of the bottom of the grooves 50 from the axis X, being preferably greater than d_(d)/2. Thus, like the grooves 50, the grooves 80 have a distal end which is set back from the distal end of the portion 40 c of the core carrying the bristles, as can be seen in FIG. 8.

Preferably, as is illustrated, the second grooves 80 are offset angularly, at their proximal end, from the first grooves 50. Thus, the first grooves 50 all have a proximal end which is distinct from the proximal end of the second grooves 80.

The grooves 50 and 80 have different cross sections. Thus, in cross section, the first grooves 50 appear more open than the second grooves 80.

FIG. 10 shows a variant which differs from the embodiment described above in that the rectilinear grooves 80 are replaced by a helical groove 80 with axis X, which extends about more than one revolution, beginning slightly back from the distal end of the portion 40 c carrying the bristles and extending as far as the proximal end.

The groove 80 can extend between a quarter turn and three turns. The helix pitch may or may not be the same as for the groove 50.

The grooves 50 and 80 intersect substantially at right angles, several times.

The variant in FIGS. 11 and 12 is similar but has a greater number of helical grooves 80, for example as many second grooves 80 as first grooves 50.

The grooves 50 and 80 can intersect at right angles, as is illustrated. The helix pitch of the grooves 50 and 80 can be the same, with only the inclination being different.

On the envelope surface S, a grid pattern is obtained that defines islands corresponding to portions each following a helical trajectory, these portions each being delimited by two consecutive grooves 50 and by two adjacent grooves 80.

The invention is not limited to the exemplary embodiments that have just been described.

The number of helical grooves 50 is not limited to five and may be lower, for example one, two, three or four helical grooves, or higher.

The pitch of the helical grooves 50 or 80 can be adjusted in such a way that each helical groove 50 or 80 extends, for example, between a quarter of a turn along the entire length of the core portion 40 c carrying the bristles, up to 3 complete turns.

The profile of the grooves 50 or 80 can be other than V-shaped and can, for example, have a rectangular shape, a semicircular shape or another shape.

The shape of the blanks 10 ⁽¹⁾ or 10 ⁽³⁾ can be obtained by cutting out the bristles with the aid of a milling device or by laser or by any other suitable technique.

It is possible for the blank 10 ⁽¹⁾ not to have conical portions, and it can have, for example, a diameter that varies with two relative extremes on either side of a relative minimum, for example what is generally a peanut shape.

A groove 50 or 80 can have a constant cross section along the core or, alternatively, a cross section that changes along the core; for example, the depth of the groove varies along the core, or its shape can vary.

Generally, it is preferable that the width at the bottom of the groove 50 or 80 is less than or equal to 0.5 mm, being for example 0.4 mm, and greater than or equal to 3 mm at the opening of the groove, for example 4.5 mm.

A distance of at least 1.5 mm between the bottom of a groove 50 or 80 and the axis X is preferred, this distance being able to be up to 5 mm, for example, for a brush with a greater external diameter of 12 mm.

The longitudinal axis of the core is preferably rectilinear; in alternatives it is curved, for example with a radius of curvature of between 30 and 200 mm.

In one variant, at least one rectilinear groove 80 is first of all formed on the blank 10 ⁽¹⁾, after which at least one helical groove 50 is formed by moving the cutting tool relative to the brush.

In one variant, at least one helical groove 50 is formed without twisting the core, and then the one or more grooves 80 are formed. 

1. A method for manufacturing a brush for applying a product to the eyelashes and/or eyebrows, comprising a core having two branches which are twisted together and bristles clamped between the branches, defining an envelope surface having at least one first helical groove and one second groove intersecting the first, the method comprising: a) producing a brush blank, of which the envelope surface defines at least one first groove, b) producing, in the blank obtained at a), at least the second groove intersecting the first groove.
 2. The method according to claim 1, the helical groove being obtained by machining the blank with a relative helical displacement between the tool and the brush.
 3. The method according to claim 1, the helical groove being obtained by machining at least one longitudinal groove, then twisting the blank about its longitudinal axis in order to give said groove a helical trajectory.
 4. The method according to claim 1, comprising the production of several first grooves.
 5. The method according to claim 4, wherein said first grooves are distributed at equal angles about the longitudinal axis of the core.
 6. The method according to claim 1, wherein the or at least one of said first grooves have, in cross section, a V-shaped profile open towards the outside.
 7. The method according to claim 1, wherein the or each first groove extends at least 180° about the longitudinal axis of the core.
 8. The method according to claim 1, wherein said one first groove extends along more than 9/10 of the length of the part of the core carrying the bristles.
 9. The method according to claim 1, comprising the production of several second grooves.
 10. The method according to claim 9, wherein the second grooves are distributed at equal angles about the longitudinal axis of the core.
 11. The method according to claim 1, wherein the or at least one of the second grooves having, in cross section, a V-shaped profile open towards the outside.
 12. The method according to claim 1, wherein the one or more second grooves being rectilinear.
 13. The method according to claim 1, wherein the one or more second grooves being non-rectilinear.
 14. The method according to claim 1, wherein the one or more second grooves being helical.
 15. A brush for applying a product to the eyelashes and/or eyebrows, comprising a core having two branches which are twisted together and bristles held by the core, defining an envelope surface having at least one first helical groove and a second groove intersecting the first one.
 16. The brush according to claim 15, comprising several first grooves and at least one second groove or at least one first groove and several second grooves, the grooves defining a grid pattern on the envelope surface on account of their intersections.
 17. Packaging and application device for applying a cosmetic product to the eyelashes and/or eyebrows, comprising: a container containing the product to be applied, an applicator comprising a brush as defined in claim
 20. 18. The method of claim 1, comprising the production of an uneven number of first grooves.
 19. The method of claim 1, wherein the or each first groove extends between a half turn and four turns about the longitudinal axis of the core.
 20. The method according to claim 1, comprising the production of an even number of second grooves.
 21. The method according to claim 9, the number of second grooves being less than or equal to the number of first grooves.
 22. The method according to claim 1, the one or more second grooves intersecting the one or more first grooves with an angle of between 60° and 120°. 